Converter vs Drill Speed
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Converter
This comprehensive utility app offers a suite of 10 powerful conversion and calculation tools, including units, currency, scientific, and more. Designed by an engineer with decades of experience, it ensures accuracy and a user-friendly interface for a wide range of applications.
- Over 1700 units in 50+ categories
- 160+ currencies supported
- Hex-Decimal-Binary and IEEE754 converters
- Scientific calculator with 38-digit precision
- Amortization calculator
- Reference charts and documents
- Customizable unit lists and favorites
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This app is a bundle of 10 great Converter & Calculator apps for one low price & more are under development: •Units Converter with over 1700 units in over 50 categories •Currency Converter with over 160 currencies •Hex-Decimal-Binary Converter •IEEE754 Floating Point Converter •Roman Numeral Converter •Drill Bit Conveter •Simple 4-Function Calculator •Scientific Converter with up to 38 digits of precision •Amortization Calculator •A Collection of Reference Charts & Documents Originally introduced in 2010 under the name of iGotCharts, this app originally contained a collection of reference charts and a modest units converter. However, it has grown to so much more since its introduction so we have changed its name to be more reflective of its full capabilities. ConvertCalc was designed and developed by a professional engineer with over 45 years of metrology experience which is reflected in the features, capabilities, and accuracy of this app. It also has a very simple and attractive user interface. You can easily disable units & charts you don't need and put them in whatever order best suits you, then save it as a favorite and quickly switch between your favorites and the app defaults. There is also a powerful search feature to simplify locating a unit of interest, regardless of category. ConvertCalc is ideal for use in the kitchen as well as for engineering, surveying & scientific applications and anything in-between. Our conversion factors are consistent with NIST publications as well as other standards agencies and organizations such as API, BIPM, IAU, IEEE, IEC, etc. Every unit is defined & described. Whimsical units & systems such as smoots, FFF (furlong-firkin-fortnight) units and the Potrzebie System of units are also included for academic usage. ConvertCalc uses 64-bit floating point math with a 52-bit significand, good for 15 significant digits of data presentation. We have developed advanced algorithms and proprietary conversion factors to maximize the computation accuracy. Where NIST or other agencies define an exact relationship between two units of measure, ConvertCalc will perform those calculations precisely without any rounding. Inexact conversions may have slight rounding in the 14th or 15th digit, which still provides at least 13 significant digits of accuracy. It also includes a Hex-Decimal-Binary Converter with IEEE754 floating point notation capability and a Roman Numeral Converter. It also includes a Simple, Scientific and Amortization Calculator. The Scientific Calculator utilizes 64-bit base-10 decimal math providing 38 digit results. General App Features: • Retina support for both iPad and iPhone • All orientations supported for all devices • Swipe gestures simplify navigation and minimize button clutter • Save favorites in any chart or unit category • Quickly alphabetize or enable/disable all items in a category • Reference charts and publications on a variety of topics • Currency converter with over 160 currencies • Extremely flexible units converter • Definitions & descriptions of every chart and unit • Print charts to Airprint printers • Email feedback or charts from within the app Units & Currency Converter Features: • Enter & convert data in decimal, scientific, or fractional numbers • Supports compound units (ft-in, st-lb-oz, hr-min-sec, etc.) • Quickly & easily adjust output mode & display precision • 64-bit math provides up to 15 significant digit conversions • Use thumbwheel picker or tabular list to view conversions • Indexed list of all individual units with powerful search feature • Attractive graphics help identify the units • Swipe up to update currency conversion rates • Tap the equal sign to quickly swap the from/to units • Tap the unit abbreviations for a description of that unit We welcome your suggestions for additional units, charts, or other features. .
Drill Speed
Easily calculate optimal drill speeds for various drill bits and materials with an intuitive icon-based interface. This app automatically adjusts options based on your selections and remembers your progress.
- Intuitive icon-based interface
- Wide selection of drill bits and materials
- Automatic option adjustment
- Detailed drill bit and material information
- Saves selection progress
- Apple Watch companion app
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Quickly and easily find optimal drill speeds for your drill bits and materials. Drill Speed has a simple icon based interface that allows you to rapidly find and select your drill bits and materials; no need to laboriously search through tables. Features - Fast and intuitive interface - Wide selection of drill bits and materials - Materials and size ranges automatically adjust to accompany the selected bit / material - Details about your drill bits and materials - Remembers your selection when you close the app, allowing you to pickup where you left off - Apple Watch companion app for quick and easy reference Get Drill Speed and put away your drill speed charts for good.
Screenshots
Verdict
The clearest difference is price: Drill Speed at Free against Converter's $2.99. On rating, review sentiment, ratings volume and update cadence there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Drill Speed is free to download; Converter costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Converter against 5.0 for Drill Speed. Both are backed by a comparable volume of ratings — 3 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
Both ship on a similar rhythm, roughly every 6 months. The most recent releases landed on October 31, 2026 and October 24, 2026 respectively.
| Parameter | Converter | Drill Speed |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 5.0 (3 ratings) | 5.0 (3 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 3 | 3 |
| Update frequency | Every 6 months | Every 6 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPod, Apple Watch |
| Requires iOS | 12.0 — better | 13.2 |
| Further details — not scored | ||
| Size | 74 MB | 41 MB |
| Age rating | 12+ | 4+ |
| Developer | Dohmann Engineering Services | Michael Bykov |
Customer experience
Converter
Drill Speed
In-app purchases
Converter
No in-app purchases
Drill Speed
No in-app purchases








